Automatically-controlled universal joint for artificial legs



Patented Sept. 15, 192 5.

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Application filed.March 29,.19242. swarm. 762,837. 7

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Be it known that. IQJUHN. LYNDALE, a citizen of. the United States, residing, at Minneapolis in the county. of Hennepin and State ofi Minnesotmliave, invented. certain new. andiuseful' Improvements in. AutomaticaIly-Cont-rolled Universal Joints: forArtificial. Legs; and. I. do: hereby declare the following to. a full; clear, and. exact. description. of? the invention,; such as will enable. others. skilled -in.the. art to which. it ap ertains to and; use the. same.

' y invention reh-testo artificial legs and has for. its object to, improve the foot. action aswill hereinafter appear.

Totlie above end, generally stated, the invention consists of the novel" devicesv and combinations v of devices hereinafter describedand-definedlin.theclaims.

In the accompanying drawings, which illnstrate the. invention, like. characters indicate throughout. the. several views. Referring. to the drawingszr i Fig. '1 is. a". sideelevationof artificial leg having my invention embodied therein and applied .to a leg having, the amputation below the knee; 1 I

Fig. 2 isa. view. partly in front elevation and partly in t'namverse vertical section takenonthe line2g -2otF. 1

Fig fiisrav detail view of sank-lejoint, was. some parts-seetimied' on the line.33 o-fiFi'g. 2, on. an enlarged scale; and

Fig; 4. is a;- detaih view withsoine parts sectioned on the line 4-4 of Fig. 1..

Ehe. artificial leg "illustrated isefor an amputation belowthe knee, and, of the parts thereof, it is important to note the foot section, 5,. shanks eraleiwerleg section 6, upper: leg section. 7, side knee; joints. 8 formed by pivotall-y connected upper and; lower metal= straps 9- .8J1df 10, respectively, and which straps Q andIQ are. secured to thee-1pper leg section 7 and lowerwleg sectionlrfi rezspectivel The parts thus far described are of stand;-

' aid and well known construction.

imprqvedianklijoint includes a transverse bearing sleeve 11 and a longitudinal seats 14in the foot section 5. Each bearing sleeve 11 and 12 is provided withav pair of axially spaced circumferential flanges 15 that hold. said. bearing sleeves against axial movement. The bearing sleeve 11 is held in its seat by aunt-equipped T bolt anchored to a transverse bar, 17 in the lower leg section 6. The'head of this- T-bolt 16 is mounted in the bearingsleeve 11 and onwliich. head saidzbearing sleeve is free to turn.

A circumferential slot .18 is formed in the bearing: sleeve 11 for the body elf/the bolt 16, and which slot permits the required rotation of said bearing sleeve on the head of the bolt 16. This body of the. T-

bolt 16 is separably connected tothe head thereof by screw threads to permit saidhead to'be inserted axiallyinto the bearing sleeve 11 and then attached to the bodyof the T- bolt.

The longitudinal bearing] sleeve 12 isheld in its half seat 14 by a. T-bolt 19 in the-same manner that the bearing sleeve 11 is held in its seat, and the body of this belt extends through a circumferential? slot 20 in the bearing sleeve 12. Said T-bolt 19 is anchored in the foot section 5 and said foot section is recessed at its u-nder side to receive 'q uired rocking movenient about the transverse axis of the foot. section 5 in respect: to the lower leg section 6 5 and the. longitudinal bearing sleeve. 12-: permits a rockingrmovement about the longitudinal axis of said foot section 5; The sides of the foot section 5 are notchedat 21 to afiordzclearance for: the

transverse bearing; sleeve 11 to permit the requiredrocking; movement of the foot tion 5. y

To-hold-the foot section. 5again'st a rocking; movement about the transverse. axis whenthe upper-legsection 7 is in an upright position, or in otherwoids when the wearer of the artificial leg is standing up, I provide a tension strap 22 having at its ends heads 23 that. are pivoted at 24 to the hinged straps 9, and which pivot point is eccentric to the hinge joint 8 and thereby imparts a crank movement to the tension strap. The end portions of the tension strap 22 are inserted through apertures 25 in the sides of the lower leg section 6, and from thence they extend downward through the open lower end of said lower leg section and alongthe sides of the foot section 5, back of the ankle joint. The intermediate portion of the tension strap 22 extends through a transverse slot 26 formed in the heel of the foot section 5 and is free to permit the required rocking movement about the longitudinal axis of said foot section on the bearing sleeve 12.

To permit the tension strap 22 to be longitudinally adjusted, the same is made in two sections, and one of said sections is provided with a loop 27 through which the otherstrap section is looped and then secured by a buckle 28. The length of the tension strap 22 is such that when the upper leg section 7 is in an upright position, the heel portion of the foot section 5 is held in engagement with the lower leg section 6 to hold the foot section 5 against rocking movement about a transverse axis.

When the upper leg section 7 is in a hori- 'zontalposition, or in other words when the wearer of the artificial leg is sitting down, the tension strap is slack, due to the crank movement of the connected ends of said strap with the hinge straps 9, and thereby permits free rocking movement about the transverse axis of the foot section .5 in respect'to the lower leg section 6. In all positions of the upperleg section 7, the foot section 5 is free to rock about the longitudinal axis for the reason that the same is free to slide on the tension strap 22.-

' By providing the ankle oint with the longit-udinal bearing sleeve 12, the foot section is free to rock about the longitudinal axis at all times, thus making it easier for the wearer of the artificial leg, especially on uneven surfaces, as it gives the foot section 5 a natural movement. When the wearer is walking, the tension strap 22 securely holds the footsection 5 from swinging on the transverse bearing sleeve 11. When the wearer is sitting down, there is suflicient slack in the tension strap 22 to permit the foot section 5 to freely move about the transverse bearing sleeve 11 so that the foot section 5 may be held in a natural position even when it is drawn backward or moved forward. 2

The above described invention has been in actual use on an artificial leg worn by the inventor and has proven highly eflicient for the purpose had in view. He has found that he can walk in a much more natural way and with less effort, and particularly so on rough and uneven ground as the foot section 5 is free to rock about the longitudinal axis.

What I claim is:

1. In an artificial leg, the combination with upper and lower leg sections connected by a knee joint, a foot section and an ankle joint connecting the foot section to the lower leg section for free pivotal movements both longitudinally and transversely, of a foot tension strap anchored to the upper leg section for crank-acting movement in respect to the knee joint and extending transversely loosely through the foot section back of the ankle joint and arranged to hold the foot section against rocking movement about a transverse axis when the upper leg section is in an upright position and to release said foot section for free pivotal movement when the upper leg section is in a horizontal position, said tension strap permitting free rocking movement about a longitudinal axis of the foot section at all times.

2. In an artificial leg, the combination with upper and lower leg sections connected by a kneejoint, a foot section and an ankle joint connecting the foot section to the lower leg section for pivotal movements both longitudinally and transversely, of a foot tension strap having its ends anchored to the upper leg section for crank-acting movement in respect to the knee joint, the intermediate portion of said tension strap being extended transversely loosely through the foot section back of the ankle joint and arranged to hold the foot section against rocking movement'about a transverse axis when the upper leg section: is in an upright position and for releasing the foot section when the upper leg section is in a horizontal position.

3. The structure defined in claim 2 in which said tension strap is longitudinally adjustable. v

4. The structure defined in claim 2 in which the end sections of the tension strap are extended upward through the interior of the=lower end portion of the lower leg section and outward through apertures in the sides thereof.

In testimony whereof I affix my signature.

JOHN LYNDALE. 

